1. Field of the Invention
The present invention relates to a lock detection device for checking whether a feed motor is in a driven state or in a non-driven state.
2. Description of Related Art
In optical disc drive apparatuses, there is conventionally used a mechanical switch or a photosensor switch as means for detecting whether a feed motor has moved a pickup until it hits a movement limit position (the innermost or outermost edge of an optical disc) (see, for example, JP-A-2000-173205, JP-A-H11-328887, and JP-A-2000-067437).
Certainly, with conventional optical disc drive apparatuses mentioned above, it is possible to detect a pickup having reached a movement limit position with the eventual aim to stop a feed motor.
Inconveniently, however, in conventional optical disc drive apparatuses mentioned above, the use of a mechanical switch or a photosensor switch results in increased component costs and increased size of a product's circuit board. In addition, in a case where a mechanical switch is used, extra attention needs to be paid to mechanical variations among individual pickups; in a case where a photosensor switch is used, extra attention needs to be paid to variations in the amount of laser light and in the amount of reflected light. These factors make it difficult to attain desired settings.
The inconveniences mentioned above are experienced not only in optical disc drive apparatuses but in products employing a feed motor in general.